I should think that the Denon 3805 at 120 WPC is enough for these highly efficient speakers (91 db at 1 meter for 1 watt), especially if your problem, as you have described, is at low listening levels.
A bigger amplifier will ONLY help at higher output levels where the lower power amplifier will CLIP...of course this can happen at low listening levels too... provided the source has a heavy amount of base like in an earthquake or dinosaur footsteps during a movie.
(Aside: Tweeters require almost no power...50 watts is about the most they ever require at any sound level....base is a different matter, however, and a single 15" cone in a professional quality sub woofer will generally need several hundred to one thousand watts....typically under powered amps will clip when driven too hard and then the distorted sound will burn or damage your tweeter as the coils get overly hot from being driven by a square wave.)
These days almost all solid state amplifiers have a VERY flat frequency response for a variety of speaker loads and Denon will be no exception.
Your room and speakers will NOT be flat frequency reponse....especially at the low end ....where the small size cabinets of the 40's will rely on speaker placement (walls) and the built in tuned port to generate low end (below 120 Hz).
A bigger amplifier will ONLY help at higher output levels where the lower power amplifier will CLIP...of course this can happen at low listening levels too... provided the source has a heavy amount of base like in an earthquake or dinosaur footsteps during a movie.
(Aside: Tweeters require almost no power...50 watts is about the most they ever require at any sound level....base is a different matter, however, and a single 15" cone in a professional quality sub woofer will generally need several hundred to one thousand watts....typically under powered amps will clip when driven too hard and then the distorted sound will burn or damage your tweeter as the coils get overly hot from being driven by a square wave.)
These days almost all solid state amplifiers have a VERY flat frequency response for a variety of speaker loads and Denon will be no exception.
Your room and speakers will NOT be flat frequency reponse....especially at the low end ....where the small size cabinets of the 40's will rely on speaker placement (walls) and the built in tuned port to generate low end (below 120 Hz).